Exam 2: Atoms Molecules and Ions

Silicon,which makes up about 25% of Earth's crust by mass,is used widely in the modern electronics industry.It has three naturally occurring isotopes,²⁸Si,²⁹Si,and ³⁰Si.Calculate the atomic mass of silicon. Isotope Isotopic Mass (amu) Abudance % ²⁸Si 27)976927 92)22 ²⁹Si 28)976495 4)69 ³⁰Si 29)973770 3)09

Many compounds can be represented with the same empirical formula.

What is the formula of hydrobromic acid?

Who is credited with discovering the atomic nucleus?

Rutherford's experiment with alpha particle scattering by gold foil established that

Which of the following is a molecular formula for a compound with an empirical formula of CH?

All neutral atoms of tin have 50 protons and 50 electrons.

Ionic compounds may carry a net positive or net negative charge.

Who discovered the neutron,the subatomic particle having a neutral charge?

The elements in Group 2A are called the ________.

Which of these pairs of elements would be most likely to form an ionic compound?

What is the term for the total number of neutrons and protons in the nucleus of each atom of an element?

Which of the following contains ionic bonding?

Which of the following substances is a molecule,but not a compound?

Which of these compounds is most likely to be ionic?

Which of these pairs of elements would be most likely to form an ionic compound?

Lead (Pb)is a main group element.

Which of these compounds is most likely to be ionic?

State the two important experimental results (and the names of the responsible scientists)which enabled the mass of the electron to be determined.

The fact that when 48.6 g of magnesium completely reacts with 32.0 g of oxygen,exactly 80.6 g of magnesium oxide is formed illustrates